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Full-Text Articles in Physical Sciences and Mathematics
Polarized Mid-Infrared Synchrotron Emission In The Core Of Cygnus A, Enrique López Rodríguez, Eric S. Perlman
Polarized Mid-Infrared Synchrotron Emission In The Core Of Cygnus A, Enrique López Rodríguez, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present high-angular (∼0". 4) resolution mid-infrared (MIR) polarimetric observations in the 8.7μm and 11.6μm filters of Cygnus A using CanariCam on the 10.4 m Gran Telescopio CANARIAS. A highly polarized nucleus is observed with a degree of polarization of 11% ±3% and 12% ±3% and a position angle of polarization of 27◦ ±8◦ and 35◦ ± 8◦ in a 0.".38 (∼380 pc) aperture for each filter. The observed rising of the polarized flux density with increasing wavelength is consistent with synchrotron radiation from the parsec-scale jet close to the core of Cygnus A. Based on our polarization model, the …
Reconstructing The Stellar Mass Distributions Of Galaxies Using S4g Irac 3.6 And 4.5 Μm Images. Ii. The Conversion From Light To Mass, Sharon E. Meidt, Trisha F. Mizusawa
Reconstructing The Stellar Mass Distributions Of Galaxies Using S4g Irac 3.6 And 4.5 Μm Images. Ii. The Conversion From Light To Mass, Sharon E. Meidt, Trisha F. Mizusawa
Aerospace, Physics, and Space Science Faculty Publications
We present a new approach for estimating the 3.6 μm stellar mass-to- light (M/L) ratio Υ3.6 in terms of the [3.6]-[4.5] colors of old stellar populations. Our approach avoids several of the largest sources of uncertainty in existing techniques using population synthesis models. By focusing on mid-IR wavelengths, we gain a virtually dust extinction-free tracer of the old stars, avoiding the need to adopt a dust model to correctly interpret optical or optical/near-IR colors normally leveraged to assign the mass-to-light ratio Υ. By calibrating a new relation between near-IR and mid-IR colors of giant stars observed in GLIMPSE we also …
Subaru Spectroscopy And Spectral Modeling Of Cygnus A, Matthew J. Merlo, Eric S. Perlman, Robert Nikutta, Christopher Packham, Moshe Elitzur, Masatoshi Imanishi, Nancy A. Levenson, James T. Radomski, Itziar Aretxaga
Subaru Spectroscopy And Spectral Modeling Of Cygnus A, Matthew J. Merlo, Eric S. Perlman, Robert Nikutta, Christopher Packham, Moshe Elitzur, Masatoshi Imanishi, Nancy A. Levenson, James T. Radomski, Itziar Aretxaga
Aerospace, Physics, and Space Science Faculty Publications
We present high angular resolution (∼0.″5) MIR spectra of the powerful radio galaxy, Cygnus A (Cyg A), obtained with the Subaru telescope. The overall shape of the spectra agree with previous high angular resolution MIR observations, as well as previous Spitzer spectra. Our spectra, both on and off nucleus, show a deep silicate absorption feature. The absorption feature can be modeled with a blackbody obscured by cold dust or a clumpy torus. The deep silicate feature is best fit by a simple model of a screened blackbody, suggesting that foreground absorption plays a significant, if not dominant, role in shaping …